1. Field of the Invention
This invention relates to a densitometer for measuring fluid density within an oil or gas well environment. Specifically, this environment will generally include exposure to high temperatures, high pressures, corrosive media, shock and vibration. Additional requirements are also a small diametrical size, low power consumption and the ability to make measurements while in motion.
2. Description of Related Prior Art
Fluid density within an oil or gas well has long been a very important parameter for well troubleshooting and evaluations. The most suitable instrument for this measurement has traditionally been based on nuclear radiation. Contemporary restrictions on the licensing and use of nuclear sources, however, have made this an increasingly unattractive approach.
Another substitute approach involves measuring the fluid head pressure differential between two points. This approach requires a differential pressure sensor capable of measuring very low pressure differences, in the presence of a potentially large static pressure. For example, the pressure head of water is one PSI for a height difference of about 27 inches. This must be accurately measured in the presence of, perhaps, 10,000 PSI static pressure. This is not only a difficult task but the high pressure environment can easily create opportunities for overpressure and destruction of the sensor.
It is an object of this invention, then, to provide a fluid density sensor suitable for making accurate density measurements within the conditions encountered in oil or gas wells.